JPS59145067A - Method and apparatus for manufacture of hollow plastic body - Google Patents

Abstract

PURPOSE:To obtain a hollow body having an excellent coating film free from contamination, damage, etc. caused by dripping, by using an exhaust means equipped with a valve means for opening and closing a flexible tube, a drain tube having a specified inner diameter and length and a mean for forcibly charging pressurized air. CONSTITUTION:A parison packed with paint is carried under a vertically standing condition to a position just below a drain tube 3, and a support 9 is lowered to bring the lower end surface 3b of the tube 3 into close vicinity to the inner bottom surface of said parison. Hereon, a valve mechanism 2 is pinched off, and pressurized air is sent from a means 7 for charging pressurized air into the parison at the same time. Hence, the paint is pushed up through the drain tube 3 and then dischrged. When the upper surface of the paint reaches the lower end surface of the tube 3, the supply of air is stopped, and the valve mechanism 2 is pinched on. Hereon, the inner diameter and length of said drain tube 3 are determined in a manner such that the paint remaining inside under the pinched- on condition does not spontaneously flow down.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a plastic hollow body;
More specifically, the present invention relates to a method and apparatus for producing a plastic hollow body coated with an inner surface coating film, including a process and apparatus for discharging the water emulsion paint filled in the plastic hollow body.

Bottles made from bottomed plastics and sled-nons by stretch molding or stretch-blow molding, such as biaxially stretched-blow molded polyethylene terephthalate bottles, have improved container properties such as gas and gas resistance, transparency, and impact resistance. It is excellent and has recently been put into practical use for storing various contents. However, when filling and sealing contents containing pressurized carbonic acid such as beer or carbonated drinks, a small amount of carbon dioxide permeates through the walls and is lost over time, while oxygen is lost.
Although it may be a little, it tends to penetrate through the wall and spoil the flavor of the contents.

As a countermeasure, the inner surface of the parison or bottle and /'-
Alternatively, a method has been proposed in which a coating film having excellent repellency against carbon dioxide and oxygen, such as a coating film made of vinylidene chloride copolymer, is formed on the outer surface.

As one method for forming such a coating film, the present inventor previously disclosed in Japanese Patent Application No. 57-182097 that a coating film was coated to form a blow molded or stretch-blow molded bottle. A method for manufacturing a glass-based IJ-son with a bottom, in which a water-based paint having a dry coating film of gas < IJ-car is applied to at least the support ring with the mouth of the bottomed/jar-non facing upward. After filling the parison to the level and discharging the filled paint, heated air is blown into the IJ in the above condition to dry the film of paint remaining on the inner surface of the parison. We proposed a method for producing Yarinon coated with a coating film. This method is different from the conventional method, for example, by holding the parison upside down with the mouth facing downward, inserting the nozzle inside the parison and spraying the paint, and then leaving it for a while to allow the paint that adhered to the inside surface to flow down. In this method, heated air is blown into the inside of Parinon to dry the film of paint remaining on the inner surface, which prevents the paint from flowing down near the mouth, especially on the end face of the mouth.
It is said that it remains in a wavy shape, that is, thick and thin parts, and even after drying, it causes unevenness near the mouth, especially on the end surface of the mouth, which impairs the sealing performance after the cap is put on. It has the advantage that problems are unlikely to occur.

However, when the paint is a water emulsion paint (hereinafter referred to as paint), it has been found that the following problems occur when the filled paint is sucked up using the conventional method.

That is, (a) after the suction is finished, the paint remaining in the suction tube flows down or drips, and the mouth of the parison is sent out from the discharge station after the paint has been discharged, and/or the discharge station for discharge. They tend to adhere unevenly to the mouths of parisons fed into the market and to their holders. As a result, the sealing performance may be impaired, or if the pH of the paint is low (sometimes around 2), the metal parts of the holder are likely to corrode.The above problems are particularly likely to occur when working at high speeds. (b) Even after the paint has flowed down or dripped, a paint film remains on the inner surface of the suction tube, but this paint solidifies when it comes into contact with air, and as the suction operation is repeated, it is absorbed. The rising tube is easily clogged.From a food hygiene perspective, this tendency occurs when a food-safe emulsifier (this type of emulsifying agent generally has a small emulsifying effect) is added in as small a quantity as possible within the emulsifiable range. ,
Especially noticeable.

The present invention aims to solve the above-mentioned problems.

In order to achieve the above object, the present invention provides a method in which the dry coating film forms a gas barrier with the mouth of the hollow plastic body facing upward.
A film of the paint that remains firmly attached to the inner surface of the glass hollow body after filling the hollow glass body with a water emulsion paint having a property to a predetermined level and discharging the filled paint in the above state. A method for producing a hollow plastic body coated with an inner coating film, the method comprising: drying under the above conditions,
The discharge of the paint includes a valve mechanism that can be opened and closed by pinching off and pinching a flexible tube, and a discharge tube that hangs down below the valve mechanism. Insert the discharge cheep of the discharge tube device, whose length is determined to prevent the paint remaining inside from falling by itself in a pinched state, to the vicinity of the bottom of the plastic hollow body filled with the paint. Then, with the mouth of the plastic hollow body closed, pinch off the valve mechanism and send pressurized air through the closed mouth to cause the paint to pass through the discharge tube. The present invention provides a method for producing a plastic hollow body coated with an inner surface coating film, the method comprising the step of pinching off the valve mechanism after discharging most of the paint by raising the body. be. Furthermore, the present invention provides an apparatus for filling a glass hollow body with an upwardly facing mouth with a water emulsion paint having a dry paint film having a svalier property to a predetermined level, an apparatus for discharging the filled paint, and an apparatus for discharging the filled paint. A manufacturing apparatus for a plastic hollow body coated with an inner surface coating film, which is equipped with a device for drying a film of the paint remaining firmly on the inner surface of the plastic hollow body, the discharge device comprising a flexible tube. A valve mechanism that opens and closes by pinching off and on, and a valve mechanism located below the valve mechanism whose inner diameter and length are such that the paint remaining inside the valve mechanism can be removed in the pinch-on state. An evacuation tube device comprising an evacuation tube that is designed to prevent gravity fall and is insertable into the plastic hollow body, a device for delivering pressurized air into the plastic hollow body, and the evacuation tube. 7° coated with an inner surface coating, characterized in that it is provided with a closing device having an inlet for the pressurized air, which closes the mouth of the plastic hollow body when the plastic hollow body is inserted into the plastic hollow body. The present invention provides an apparatus for manufacturing a Shirasuk hollow body.

The present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the paint discharge bag #1 includes a valve mechanism 2 having a flexible tube 2a, a discharge tube device 4 having a discharge tube 3 located below the valve mechanism 2, and・e Mouth part 32 of IJ sonon 1 (Fig. 3)
and a pressurized air supply device 7 for supplying pressurized air into the Y9 IJ SO/31 through the supply hole 6 provided in the closure #54. .

The flexible teak 2a of the valve mechanism 2 has a low pH of the paint 8 passing through it, that is, the water emulsion paint.
For example, it is made of glass or elastomer, preferably silicone rubber or Teflon, etc., so as to be easily corroded even when the pH is 2). There is. The support 9 is configured to be movable up and down by a drive mechanism (not shown).

The upper end 2a1 of the flexible tube 2a is fitted onto a branch pipe 11a hanging down from the discharge pipe 11 for the paint 8, and the lower end 2a2 thereof is fitted onto the upper end of the discharge tube 3. The discharge pipe 11 is connected to a paint tank (not shown).

One side of the central part 2a3 of the flexible tube 2a is in contact with the cylindrical fixed body 12, and the central part 2a faces the fixed body 12.
A presser 13 is provided to allow pinching of 3. The holding tool 13 is fixed to the tip of the piston rod 14 of the air cylinder/goo 15, and by the operation of the air cylinder 15,
It is configured to move horizontally along the id 16.

When the presser 13 moves to the right until the opposing inner surfaces of the central portion 2a3 of the flexible tube come into contact with each other (the state shown in FIG. 1) (in this specification, this state is referred to as pinch-on). ), the valve mechanism 2 closes, and conversely, the presser 13 moves to the left, and the center part 2a3 that is in contact with the presser 13
When the part becomes almost straight (in this specification,
This state is called pinch-off), and the valve mechanism 2 is fully open.

Harz' mechanism 2 is always in a pinch-on state.

Note that 17a and 17b are air conduits for the air cylinder 15, and are fixed to the horizontal plate 9b of the seat 9.

The discharge tube 3 is made of a tube made of hard-to-flex plastic, resin, or stainless steel, and is fixed to the support 9 via an arm 18 and a holder 10.

The diameter of the discharge tube 3 and the flexible tube 3, as well as the length from the central portion 2a3 to the lower end surface 3bt of the discharge tube 3, are such that, in a pinch-on state, the material 8 inside is free. It is determined that it will not fall (due to surface tension). Therefore, their dimensions are controlled by the specific gravity, viscosity, surface tension, etc. of the paint, but usually the inner diameter is about 6.
(2) Below, the above conditions are satisfied when the length is approximately 300 cylinders.

In order to increase the discharge speed and increase productivity, the inner diameter must be as large as possible within the range that satisfies the above conditions (
1 mm or more) is desirable. The length still satisfies the above conditions, and the lower end surface 3b is approximately the same as the bottom 3 of the parison.
It is desirable that the length be long enough to reach 6. Discharge tube 3
is slidably inserted through the through hole 19a of the closing portion 19 of the closing device 5.

20 is an O-ring for sealing.

The closure device 5 includes a closure part 19 and a support part 21 that supports the closure part 19. The closing portion 19 is formed with the aforementioned through hole 1.9a extending in the axial direction. Through hole 19
The upper part of a has an inner diameter that allows the discharge tube 3 inserted therein to slide, but the inner diameter of the middle part in the height direction is set slightly larger than the outer diameter of the discharge tube 3, An annular pressurized air guide hole 2 is provided between the tube 3 and the tube 3.
2 is formed.

At the lower part of the closing part 19, an annular hooking 23 is provided which surrounds the discharge tube 3 and is made of an elastic body (for example, a silicone comb) and which can be engaged with the mouth end surface 32a of the O-linon 31. There is. The annular JP packing 23 is formed with a plurality (four in the figure) of pressurized air inlet holes 6 that communicate with the guide hole 22 .

The support part 21 is equipped with a vertical rod 26 and a coil spring 27 surrounding the vertical rod 26, and as shown in FIG. Guide cylinder 29 fixed to horizontal plate 9b
Although the upper end surface 29a is engaged, when the closing part 19 is pushed up, the vertical rod 26 also rises and the coil spring 2
7 acts on the reaction force.

The pressurized air supply device 7 includes a main pipe 24 fixed to the arm 18 and a branch pipe 25, and the main pipe 24 (d) is connected to a pressurized air source via a valve (not shown).
is connected to the guide hole 22.

An example of a method for manufacturing a parison whose inner surface is coated with a paint film, including the steps of: discharging the paint filled in the parison using the above-described discharge device I, will be described below.

In Figure 3, 31 is a bottomed, OIJ sonon,
flJ, t is made of saturated polyester such as polyethylene terephthalate, polypropylene, etc., and is usually formed by injection molding. 32 is the mouth;
33 is a threaded portion, and 34 is a support ring, which retains its original shape and thickness even after being formed into a bottle (not shown) by blow molding or stretch-blow molding. Note that when the support ring 34 is plugging the cap into the threaded portion 33, it engages with the support body (not shown), and the axial force due to plugging is applied to the body and bottom of the cap, which has a relatively small strength. This is normally provided in order to prevent this from occurring.

The generally depending portion of the parison 31 below the support ring 34, or body 35, primarily constitutes the relatively thin shoulder and body of the bottle formed. Kade Ya Rinon 3
The bottom 36 of 1 will primarily be the bottom of the bottle formed. Therefore, in order to improve the sparring resistance of the formed bottle, it is necessary to coat the inner surfaces (and the outer surfaces, if necessary) of the body 35 and bottom 36 of FIJ Sonon 1 with a gas clear coating. good.

Since the portion above the support ring 34 remains thick (for example, about 1 to 4 wn) even after being formed into a bottle, it does not necessarily need to be coated with a Svalier coating. On the contrary, during this coating operation, the paint often adheres unevenly to the end surface 32a of the mouth portion 32, which tends to result in poor sealing as described above, so it is preferable not to coat the above-mentioned upper portion.

As shown in FIG. 3, the parison 31 is inserted into the through holes 37b of the holders 3, .
7a, the filling device of the filling station (
(not shown) and is filled with the paint 8, preferably to approximately the level of the support/gage 34, through a conduit and a filling nozzle (not shown) from the aforementioned paint film/layer.

As mentioned above, paint 8 has a dry coating film made of gas (oxygen).

It is a water emulsion paint that has barrier properties (such as nitrogen and carbon dioxide). This type of paint includes copolymers consisting of vinylidene chloride monomers and acrylic or methacrylic monomers, or vinylidene chloride monomers, heavy acrylic or methacrylic monomers, and ethylenically unsaturated Examples include aqueous latexes of copolymers made of monomers.

The OIJ sonon 1 filled with the paint 8 is then conveyed in an upright position to a discharge station and stops directly below the discharge tube 3. Immediately, the support 9 descends, and the mother kinder 23 of the closing part 19 touches the mouth end surface 32a of the parison.
The support 9 further descends until the lower end surface 3b of the discharge tube 3 approaches the inner surface of the bottom 36 of the parison, as shown in FIG. Along with this, the vertical iron 26 rises, and the coil spring 27 is compressed.
The end face 32a of the parison opening 32 is sealed via a cover 23 in the closing part 19.

When the lower end surface 3b reaches a certain level close to the inner surface of the bottom part 36, the support 9 stops based on a signal from a limit switch (not shown), the pulp mechanism 2 immediately pinches off, and pressurized air is supplied immediately. A pulp (not shown) of the device is opened and pressurized air 38 is introduced into the tube 31 through the inlet hole 6 . However, the paint 8 in the OIJ sonon 1 is pushed up and discharged through the discharge tube 3, sent to the aforementioned paint tank, and collected.

When the upper surface 8a of the paint 8 reaches almost the lower end surface 3b of the discharge tube 3, the pulp of the pressurized air supply device closes, the supply of pressurized air stops, and Pulp mechanism 2 is also pinched on. For example, a timer signal can be used as the signal. This is because by keeping the filling amount, pressurized air pressure, and pulp opening constant, the level of the upper surface 8a of the paint becomes a function of the pressurized air supply time. Raise and return the evacuation tube 3 and closure 19 to their original position above the No. 9 IJ sonon 1. The parison 31 is then conveyed to the next re-discharging station in an upright position. (Other types of pulp, such as rotary pulp, are susceptible to shock), so the paint in the discharge tube 3 may fall during conveyance, causing the parison 3 to
There is no risk of it adhering to the mouth portion 32 or the holder 37 of the device. Therefore, since there is always paint 8 inside the discharge tube 3, there is a risk that the paint will solidify on contact with air inside, and the discharge tube 3 will be clogged. When the amount of emulsifier added is small), there is generally a tendency to coagulate when shearing force is applied, but in the case of the pulp mechanism 2, almost no shearing force acts.

Therefore, unlike rotary pulp, there is no risk of coagulation on the sliding surface and the pulp becoming inoperable.

At the re-ejection stay, some of the paint 8 that has flowed down the inner surface of the body 35 of the parison 31 and accumulated on the bottom 36 after being ejected is removed.
Discharge via a suction pipe (not shown). The time from the end of the first discharge to the start of re-discharge is preferably about 15 to 30 seconds. In order to prevent internal clogging of the suction tube, it has a double tube structure, and water flows down between the outer jacket and the inner tube, and at the lower end, paint is sucked up along with the water into the inner tube. Type wicking/mother Eve is preferably used. The paint in this case will not be collected. By doing so, a paint film having a relatively uniform thickness is formed along the inner surfaces of the body portion 35 and bottom portion 36 of the Noyarinon 31.

Next is one in the same upright position! As shown in FIG. 4, the heated air nozzle 39 is inserted into the parison 31 and
Heated air 4o at 0° C. is blown into the parison 31 to dry the paint film, thereby obtaining the parison 31 with the dry paint film 41 formed on the inner surface. The thickness of the coating film 41 obtained by one operation is usually 10 to 20 μm, so if a thicker coating film is to be obtained, the above operation may be repeated.

The parison 31 coated with the gas barrier coating film 41 is heated to a predetermined temperature as described above, and then subjected to blow molding or biaxial stretching-blow molding to obtain a bottle with improved sparring properties. be able to.

The present invention is not limited to the above embodiments,
After filling the paint, for example directly into the bottle, as described above,
A gas barrier coating film may be formed on the inner surface of the bottle by discharging the bottle and drying the coating film formed on the inner surface.

According to the present invention, filling and discharging the water-emulsion paint and drying the remaining paint film are performed while the plastic hollow body is in an upright state to form a dry paint film on the inner surface.
The level at which this coating film is formed can be freely determined, so that the coating film does not cover the end face of the mouth or its vicinity.
It has the effect that a plastic hollow body with excellent sealing properties and excellent sealing properties can be manufactured, and furthermore, the paint can be recovered and used.

In addition, since a pulp mechanism with no sliding surfaces is used, even when discharging water emulsion paint with a small amount of emulsifier added,
This has the advantage that there is no risk of the valve becoming clogged or unable to open or close.

Furthermore, pressurized air pushes up the paint surface and causes the paint to rise inside the discharge tube, causing the paint to be discharged.
The paint can remain in the discharge tube even after discharge. The inner diameter and length of the discharge tube are determined to prevent the paint remaining inside from falling by itself when the pulp mechanism is in a pinch-on state, so that the paint that has fallen naturally will be removed when the hollow glass body is transported. , there is no risk that the sealing performance will be impaired due to rigid attachment to the end surface of the mouth part. Another advantage is that there is no risk that the paint in the discharge tube will solidify upon exposure to air and clog the discharge tube.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of the ejection device in an apparatus according to an embodiment of the present invention, Fig. 2 is a bottom view of the closed part of the ejection device of Fig. 1, and Fig. 3 is the ejection device of Fig. 1. A vertical cross-sectional view of the main part showing the state in which the pigment in the Ritz is being discharged using the
FIG. 4 is a longitudinal cross-sectional view showing an example of the □ state in which the film of paint remaining on the inner surface of the O-litz is dried. DESCRIPTION OF SYMBOLS 1... Discharge device, 2... Pulp mechanism, 2a... Flexible tube, 3... Discharge tube, 4... Discharge tube device, 5... Closing device, 6... Delivery Entrance, 7.
Pressurized air supply device, 8...Water emulsion/paint, 31
...Bottomed parinon (plastic hollow body), 32...
Mouth part, 39... Heating air nozzle (drying device), 41.
・Dry coating film.

Claims (2)

[Claims] (1) With the mouth of the hollow plastic body facing upward, fill the hollow plastic body with a water emulsion paint whose dry coating film has sparring properties to a predetermined level, and place the filled paint in the above state. A method for manufacturing a plastic hollow body coated with an inner surface coating film, wherein the paint film remaining on the inner surface of the plastic hollow body is dried in the above-mentioned conditions after the paint is discharged. It is equipped with a pulp mechanism that opens and closes by pinching off and pinching a flexible pulp, and a discharge tube that hangs down below the pulp mechanism. In this state, insert the discharge tube of the discharge tube device, which is designed to prevent the paint remaining inside from falling naturally, to the vicinity of the bottom of the plastic hollow body filled with the paint, and then insert the discharge tube into the plastic hollow body filled with the paint. With the chamber closed, pinch off the pulp mechanism and send pressurized air through the closed mouth to raise the paint through the drainage cheep and remove the bulk of the paint. A method for producing a plastic hollow body coated with an inner surface coating, comprising the step of pinching off the pulp mechanism after discharging the part. (2) A device for filling a hollow body of plastic with an upwardly facing mouth with a water-emulsion paint having a dry coating film having a property of spreading, and a device for discharging the filled paint; A manufacturing apparatus for a plastic hollow body coated with an inner surface coating film, which is equipped with a device for drying a film of the paint remaining on the inner surface of the plastic hollow body, the discharge device pinching a flexible tube.・A pulp mechanism that opens and closes by turning off and pinching on, and a pulp mechanism located below the pulp mechanism whose inner diameter and length are designed so that the paint remaining inside will fall naturally when the pulp mechanism is in the pinch-on state. an evacuation tube device having an evacuation tube insertable into the plastic hollow body, and a device for delivering pressurized air into the plastic hollow body; 1. An apparatus for producing a plastic hollow body coated with an inner surface coating film, comprising a closing device having an inlet for the pressurized air, which closes the mouth of the plastic hollow body when inserted into the plastic hollow body.